Positive retracting mechanical expansible shaft

Abstract

An expansible shaft in which a screw that is rotationally and axially movable relative to the housing is rotatably connected to the operating rod so that clockwise screw rotation moves the rod axially in one direction and counterclockwise screw rotation moves the rod axially in the opposite direction.

What is claimed is: 
     
       1. An expansible shaft for engaging and rotating the core of a roll comprising: an axially-extending housing;   an operating rod mounted coaxially of said housing and arranged for movement axially relative to said housing;   a core engager movable radially relative to said housing and said operating rod between an expanded position in which said core engager extends beyond the outer wall of said housing and a retracted position in which said core engager is positioned radially within said expanded position thereof;   an actuator mounted on said rod and arranged to move axially in response to axial movement of said rod, said actuator axial movement causing said core engager to move towards said expanded position in response to axial movement of said rod;   an actuating screw threadingly engaging said housing and being rotationally and axially movable relative to said housing, said screw being mounted coaxially of and in general axial alignment with said rod; and,   means for connecting said screw to said rod to permit relative rotation of said screw and rod and to move said rod axially in one axial direction in response to clockwise rotation of said actuating screw and in the opposite axial direction in response to counterclockwise rotation of said actuating screw,   said rotatable connecting means comprising a first pair of generally oppositely axialy facing surfaces and a second pair of generally oppositely axially facing surfaces axially spaced from said first pair of surfaces,   the surfaces of said first pair of surfaces being attached to one of said rod and said screw,   the surfaces of said second pair of surfaces being attached to the other of said rod and said screw,   said surfaces of said first pair being positioned axially between said surfaces of said second pair whereby screw movement in one axial direction causes one surface of said first pair to contact one surface of said second pair and push said rod in said one direction and screw movement in the opposite axial direction causes the other surface of said first pair to contact the other surface of said second pair and push said rod in said other direction,   said one surface of said first pair of surfaces comprising a segment of a ball surface facing in one generally axial direction, said ball being attached to one of said rod and said screw, and   said one surface of said second pair of surfaces comprising a segment of the inner surface of a socket that generally envelopes said ball and is attached to the other of said rod and said screw.   
     
     
       2. The shaft of claim 1 further comprising a spring mounted within said shaft and arranged to exert axially directed force on said rod. 
     
     
       3. The shaft of claim 2 further characterized in that said spring biases said screw axially in an opposite direction to that which said screw moves to secure said core-engager toward said expanded position. 
     
     
       4. The shaft of claim 2 further characterized in that said spring biases said rod in a direction opposite to that which said rod moves to secure said core-engager towards said expanded positon. 
     
     
       5. The shaft of claim 2 further characterized in that said spring is positioned to apply axial force to the end of said rod opposite said screw. 
     
     
       6. The shaft of claim 5 further comprising a second spring positioned axially between said screw and said first rod end, said second spring tending to force said screw axially away from said rod. 
     
     
       7. An expansible shaft comprising: an axially-extending housing;   an operating rod mounted coaxially of said housing and arranged for movement axially relative to said housing;   a core engage movable radially relative to said housing and said operating rod between an expanded position in which said core engager extends beyond the outer wall of said housing and a retracted position in which said core engager is positioned radially within said expanded position thereof;   an actuator mounted on said rod and arranged to move axially in response to axial movement of said rod, said actuator axial movement causing said core engager to move towards said expanded position in response to axial movement of said rod;   an actuating screw threadingly engaging said housing and being rotationally and axially movable relative to said housing, said screw being mounted coaxially of and in general axial alignment with said rod; and   a means for connecting said screw to said rod to permit relative rotation of said screw and rod and to move said rod axially in one axial direction in response to clockwise rotation of said actuating screw and in the opposite axial direction in response to counterclockwise rotation of said actuating screw,   said connecting means comprising a ball member fixed to one of said screw and said rod, and a socket member connected to the other of said screw and said rod,   said socket member defining a cavity sized to receive and allow rotation of said ball therein, and further defining an entrance passage thereto configured and sized to prevent passage of said ball therethrough during operation of said shaft.   
     
     
       8. The shaft of claim 7 further characterized in that said ball member is fixed to said screw and said socket member is fixed to said rod. 
     
     
       9. The shaft of claim 8 further characterized in that said ball member comprises a connector shaft attached at one end to said screw and at the other end to a generally mushroom-shaped head having at its base an annular surface perpendicular to the axis of said shaft and facing towards said screw, and said socket member includes a generally cylindrical bore having a plurality of circumferentially-spaced slots through the wall thereof extending from one end thereof, the portion of said bore nearer said end having a diameter less than that of said head and having an interior annular step arranged to engage said surface of said head, and an interior portion of said bore having a diameter not less than and being arranged to receive said head.   
     
     
       10. The shaft of claim 9 wherein said slots define a plurality of axially-extending fingers, and the ends of said fingers at said end of said socket member are movable radially to permit said head to be inserted axially into said interior portion of said bore. 
     
     
       11. The shaft of claim 9 further characterized in that a spring surrounds said shaft and engages the adjacent ends of said screw and said socket member and biases them axially apart. 
     
     
       12. The shaft of claim 7 wherein said connecting means comprises a spring member mounted to bias said ball member and said socket member axially apart.